I sew all of my borders into strips, then attach to my quilts. That way, I don't have to measure but one time in both directions. If you sew each border on separately, then you have to measure both directions after each border is added, leaving more chance for stretching, etc. My preference is mitered borders, so sewing all the borders together first before sewing onto the quilt works great. I just finished a quilt that had seven borders.